1. Field of the Invention
The present invention is related with the memory management in environments of limited resources, that is, in systems with reduced storage and processing capacity, like those found for example on a smart card.
In more particular terms, the invention refers to a method of managing the data storage resources of volatile memory, the object of which is to reduce the size of volatile memory necessary to implement the stack of the system, and thereby to reserve more volatile memory available for other needs or procedures of the system or of other applications
It is also an object of the invention to provide processing means which operate according to the memory management method referred lo above.
2. Description of Related Art
The portable data processing systems limited in volatile memory, like those found for example on a smart card, suffer major restrictions in the use of this type of memory in the system due to the scant size of memory available In multi-application systems, these restrictions are aggravated even more because each application can require the use of this type of memory for internal use, without its reuse or sharing being desired with other applications.
Conventionally the stack consists of a data structure of the type LIFO (Last In, First Out—the item of data last stored is the first one recovered) and a pointer which indicates which is the last item stored The stack is used to control the execution of the programs (linkage of functions and local variables). There is a size of volatile memory reserved for the stack, the stack pointer indicates the level of use of the same
The stack is usually filled toward lower memory locations, with the limitation of the size resented for this. In the event that the established limitation is exceeded, the system should abort the execution of the process in course and report the error, since if it was not controlled it could cause a substantial error in the system and could signify a security hole